The present exemplary embodiment relates to a method for dental restoration. It finds particular application in conjunction with the direct intra-oral modification of a non-titanium abutment component, and will be described with particular reference thereto.
The central pulp inside a human tooth is surrounded by a calcareous substance known as dentin, and the pulp communicates with arteries, veins, and nerves. The tooth projects from sockets or alveoli dentalis which are depressions in the alveolar bone of the maxillae (upper jaw) or mandible (lower jaw). The portion of the tooth that actually fits into the socket is formed into one or more roots. The projecting portion of the tooth (known as the crown) comprises grinding surfaces and is covered by a calcified connective tissue known as enamel. Gum or gingival tissue covers the base of the crown and project between adjacent surfaces of teeth; and anchors teeth in place.
Tooth loss may be caused by various diseases such as dental caries, tooth defects, pulpitis, physical injuries, gum disease, and periodontal diseases. Periodontal disease is caused by a sticky film of bacteria called plaque, which over time hardens into calculus. Mild inflammation such as gingivitis may have symptoms of red, swollen and bleeding gums, which may spread to other supporting structures including alveolar bone, producing a more advanced stage of periodontal disease known as periodontitis. The gums recede or pull away from the teeth, resulting in the formation of pockets between the teeth and gums. As the disease progresses, teeth become loose, often necessitating extraction. Thus, periodontal disease is a major cause of tooth loss.
There have been a variety of known methods devised to implant and secure a dental prosthesis. The most common type of implant is endosseous, in which an implant is first surgically placed into the patient's jawbone. The implant serves to mimic a root structure and protrudes through the gum to hold an abutment adapted to receive a dental prosthesis. A common abutment is a substantially cylindrical device that is typically screwed into the implant, and the crown is then affixed on top of the abutment. A traditional way known to a skilled dentist in dental restoration of implant includes the following 12 steps: (1) take off the sealing cap; (2) prepare the tray, and try the impression tray on, drawing the line to cut and open the window to allow the impression coping to stick out (known as open-tray technology); (3) put regular impression coping on, and screw tight; (4) put impression material into the prepared tray; (5) press the impression on top of the impression coping, and wait until set; (6) unscrew the impression coping; (7) place wax to close the open window around the portion sticking out of the impression coping; (8) take off the impression tray with impression coping on it; (9) connect the implant analog with the impression coping and send all together to dental lab; (10) A laboratory technician will pour material and prepare a stone model, then send it back to the dentist; (11) the dentist chooses the abutment he or she thinks will fit the stone model best, and will send it back to the laboratory; and (12) the laboratory technician adjusts the abutment, then may send it back the dentist to try on the patient's mouth, then re-adjusts the abutment again based on the dentist's prescription, and makes the crown on top of the abutment.
U.S. Pat. No. 4,975,059 to Sendax discloses a cast dental implant abutment. As shown in FIG. 1, a cast dental implant abutment 10 is preferably prefabricated from an acrylic plastic. The abutment 10 has an externally threaded lower section 12 which precisely threads into the individual internal threads of a cylinder-type HA-coated implant (not shown). The acrylic abutment 10 may be either machined or injection-molded. The outer dimension of the abutment 10 corresponds to the outer dimension of the implant type it is intended to match up with. The top of the abutment 10 has a cross-hatch groove system 14 recessed in its surface 16 to permit screwing down the abutment 10 into the implant (not shown) in the jawbone of a patient. This is first done after the implant has integrated with the bone and been surgically uncovered. At this time the abutment 10 is screwed down into place very lightly and with a little lubricant to permit easy unscrewing without fracturing the acrylic. It is then cut off at an angle to form surface 18 to bring it into normal relationship to the other implants or abutment teeth in the arch, and also into normal relation to the opposite (opposing) arch or jaw. This redressing or redirecting of the angulation of the abutment 10 is the key to the flexibility of the abutment 10 and its universal applicability. As taught in claim 1 in Sendax, the plastic dental implant abutment 10 will be cast into a metal (and final) abutment which maintains the ability of mating with the internally threaded implant.
It is evident that the abutment 10 in U.S. Pat. No. 4,975,059 to Sendax remains a temporary abutment, and functions as an analogue (or model) of the final or permanent abutment to be prepared in later steps. The abutment 10 will be sent to a lab for the fabrication of the final or permanent abutment. As Sendax discloses, final fabrication of the custom abutment is then completed on the indirect laboratory model, cast, finished, and cuff polished before the device is returned to the mouth and screwed into place.” (Lines 65-68, Column 2) After the dental restoration is completed, the temporary abutment 10 will be discarded, and replaced with the final or permanent abutment, i.e. a custom abutment that will be used in the patient's mouth for many years or decades.
Known dental restoration processes are disadvantageous in that they are procedurally very complicated, causing low penetration rate for dental implants. Now less than 5% general dentist can do surgical placement of dental implant, and less than 10% of general dentist actually do implant restoration due to the complications of the current technology. To increase the penetration rate of the implant in restoration dentistry, a dentist needs to use a simplified restoration procedure and technology, which should be straightforward, cost effective, and include a minimal number of office visits. The need is also highlighted by the burden that in order to properly transfer an accurate model of the soft tissue in the area of the planned implant, most abutment systems now use closed tray or open tray impression technologies. These require a modification of the abutment in the lab by a dental lab technician; or in an alternate approach, a doctor uses a temporary plastic abutment, modifies it in the patient mouth, then sends it to a lab to cast the metal abutment base on the shaped temporary abutment. Such complicated procedures significantly increase the lab fees, reduce dentist's profit from ¼ to ⅓, and/or costs the patient more in fees and time.
Another problem is that dental implant systems in prior art require a vast array of threaded coronal prosthetic attachments to accommodate different restoration methods utilized in the dental practice. Currently, there are three primary restoration methods, a fixed single or multiple unit cementable crown prosthesis, a removable single or multiple unit screw retained prosthesis or a removable overdenture prosthesis. In order to accommodate these different restoration methods, a vast inventory of different components are needed, requiring a significant investment in time and money by dental professionals.
Still another problem associated with dental implants is the inability to select the final abutment by the surgeon and restorative dentists. The dental laboratory typically decides what the configuration of the abutment will be by analyzing the plaster impressions taken of the patient's mouth. This prevents the surgeon or restorative dentist from being able to observe and possibly correct any angle problem or tissue height discrepancy.
Advantageously, the present invention provides a new method for dental implant restoration, which exhibits numerous merits such as simplified procedure, cost-effectiveness, reduction of chair time, elimination of 1-2 lab trips, and reduction of office visits. In some embodiments, the present invention enables an oral surgeon or restorative dentist to modify the abutment at any time so as to allow for the ideal shape, contour, and margin placement. The method of the invention can be completed in the dentist's office with minimal to no margin existing between the gum tissue and the crown once it is installed, and eliminate the need of sending the abutment system back to the dental laboratory for adjustment.